From dca49e73e50fdc5b4140af7a1366bbb6b143dbbd Mon Sep 17 00:00:00 2001
From: Double Sine <xiao_ai_yu@live.cn>
Date: Mon, 14 Jan 2019 15:13:44 +0800
Subject: [PATCH] Add FileMapper.hpp

---
 navicat-patcher/FileMapper.hpp | 96 ++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 navicat-patcher/FileMapper.hpp

diff --git a/navicat-patcher/FileMapper.hpp b/navicat-patcher/FileMapper.hpp
new file mode 100644
index 0000000..03340eb
--- /dev/null
+++ b/navicat-patcher/FileMapper.hpp
@@ -0,0 +1,96 @@
+#include "Exceptions.hpp"
+#include "ResourceGuardWin32.hpp"
+#include <string>
+#include <utility>
+
+#if defined(UNICODE) || defined(_UNICODE)
+using String = std::wstring;
+#else
+using String = std::string;
+#endif
+
+namespace Patcher {
+
+    class FileMapper {
+    private:
+        ResourceGuard<FileHandleTraits> _FileHandle;
+        ResourceGuard<GenericHandleTraits> _FileMapHandle;
+        ResourceGuard<MapViewTraits> _FileView;
+    public:
+
+        static bool IsExist(const String&& FilePath) {
+            DWORD dwAttr = GetFileAttributes(FilePath.c_str());
+            if (dwAttr == INVALID_FILE_ATTRIBUTES) {
+                if (GetLastError() == ERROR_FILE_NOT_FOUND)
+                    return false;
+                else
+                    throw SystemError(__BASE_FILE__, __LINE__, GetLastError(),
+                                      "GetFileAttributes fails.");
+            } else {
+                return (dwAttr & FILE_ATTRIBUTE_DIRECTORY) == 0;
+            }
+        }
+
+        template<typename _Type>
+        _Type* GetView() const noexcept {
+            return reinterpret_cast<_Type*>(_FileView.GetHandle());
+        }
+
+        void MapFile(const String& FileName) noexcept {
+            ResourceGuard<FileHandleTraits> TempFileHandle;
+            ResourceGuard<GenericHandleTraits> TempFileMapHandle;
+            ResourceGuard<MapViewTraits> TempFileView;
+
+            TempFileHandle.TakeHoldOf(
+                CreateFile(FileName.c_str(),
+                           GENERIC_READ | GENERIC_WRITE,
+                           NULL,
+                           NULL,
+                           OPEN_EXISTING,
+                           FILE_ATTRIBUTE_NORMAL,
+                           NULL)
+            );
+            if (TempFileHandle.IsValid() == false)
+                throw SystemError(__BASE_FILE__, __LINE__, GetLastError(), 
+                                  "CreateFile fails.");
+
+            TempFileMapHandle.TakeHoldOf(
+                CreateFileMapping(TempFileHandle,
+                                  NULL,
+                                  PAGE_READWRITE,
+                                  0,
+                                  0,
+                                  NULL)
+            );
+            if (TempFileMapHandle.IsValid() == false)
+                throw SystemError(__BASE_FILE__, __LINE__, GetLastError(), 
+                                  "CreateFileMapping fails.");
+
+            TempFileView.TakeHoldOf(
+                MapViewOfFile(TempFileMapHandle,
+                              FILE_MAP_READ | FILE_MAP_WRITE,
+                              0,
+                              0,
+                              0)
+            );
+            if (TempFileView.IsValid() == false)
+                throw SystemError(__BASE_FILE__, __LINE__, GetLastError(), 
+                                  "MapViewOfFile fails.");
+
+            _FileView.Release();
+            _FileView = std::move(TempFileView);
+            _FileMapHandle.Release();
+            _FileMapHandle = std::move(TempFileMapHandle);
+            _FileHandle.Release();
+            _FileHandle = std::move(TempFileHandle);
+        }
+
+        void Release() {
+            _FileView.Release();
+            _FileMapHandle.Release();
+            _FileHandle.Release();
+        }
+    };
+
+}
+